Phase transition in Pb/sub 0.88/Ln/sub 0.08/Ti/sub 0.98/Mn/sub 0.02/O/sub 3/ (Ln=La, Sm, Eu) piezoelectric transducers, using radiation and emissivity [biomedical US transducers application]

We report a new method to determine the phase transition in piezoelectric ceramic by means of the radiation that they emit when it is subjected to different temperatures. The experiment is performed in piezoelectric ceramic based on PbTiO/sub 3/ modified by the partial substitution of rare earths for Pb in the Pb/sub 0.88/(Ln)/sub 0.08/Ti/sub 0.98/Mn/sub 0.02/O/sub 3/ system (Ln = La, Sm, Eu). Also starting from the measurement of the emitted radiation, the value of the emissivity is calculated for each type of piezoelectric ceramic.